When a parachutist begin approaches the ground for a landing they begin a flare. Many injuries upon landing due to improper procedures during this last phase of the parachute flight in manned and unmanned parachute systems. In 2015, there were reported 41 fatalities associated with parachuting worldwide many of those injuries due to a hard landing. See http://www.dropzone.com/fatalities/ (last accessed Feb. 22, 2017). For example, an experienced solo skydiver died due to a hard landing at Dillingham Air Field in Hawaii on Oct. 22, 2016. See http://khon2.com/2016/10/22/skydiver-injured-in-landing-at-dillingham-air-field/ (last accessed Feb. 22, 2017). Military parachute jumps are particularly subject to a hard landing during nighttime jumps. The key to a safe landing is accurate knowledge of the parachutist's distance to the ground.
The most common parachute altimeter is based on the ambient pressure, which are sometimes called mechanical altimeters as they depend on the status pressure of the ambient air. As the parachutist descends the ambient pressure increases. Once the ambient pressure reaches a predetermined level, the altimeter alerts to the proximity to the ground. Another technology employed is using GPS to determine the altitude of the ground at the location of the parachutist. Unfortunately, there is a lag time in using all GPS devices that makes their use too inaccurate for parachute landings. The main and major problem with altimeters based on ambient pressure is that they are inherently inaccurate to +/−30 feet and depend on calibration to the local elevation. The altimeter currently used to determine the flare usually 20 ft and down height for the jumper it is strictly a visual gauge by the solo jumper. Further, the vast majority of these altimeters are placed on the wrist of the parachutist. The parachute flare at this point in the jump requires split second decision making of the parachutist. At the point where the parachutist is required to flare the parachute for a landing, the user cannot spare valuable time to glance at the wrist mounted altimeter.
The purpose of the embodiments described herein is to provide an accurate and reliable device to determine altitude, distance and velocity to the ground for recreational and military parachutists as well as unmanned cargo delivery systems.